Just a few hours after telling USA TODAY Sports that Sunday would be ''business as usual,'' and Stewart would race as scheduled, the team reversed course.

Greg Zipadelli, vice president of competition for Stewart-Haas Racing, announced the three-time Sprint Cup champion would not start the Cheez-It 355 at The Glen a day after striking and killing an on-foot driver in a sprint car race.

Regan Smith started in his place.

"It's an emotional time right now," Zipadelli said.​

Stewart released a statement after the race began that read:

"There aren't words to describe the sadness I feel about the accident that took the life of Kevin Ward Jr. It's a very emotional time for all involved, and it is the reason I've decided not to participate in today's race at Watkins Glen. My thoughts and prayers are with his family, friends and everyone affected by this tragedy."

Zipadelli, who said the team would not discuss last night's incident, said he met with Stewart this morning and "he feels strongly this is the right thing to do. We at SHR support it and agree with it. It's a difficult time for both parties. This is what we feel is right and we're supporting Tony in it."

Zipadelli originally told USA TODAY Sports that Stewart would start today and ''we're business as usual.''

Stewart struck and killed driver Kevin Ward Jr., 20, who approached his car on-foot after an on-track incident at Canandaigua (N.Y.) Motorsports Park, about an hour north of Watkins Glen International.

Friends and family members of Ward Jr. are gathering at the Ward home in Port Leyden, N.Y.

The family has issued this statement: "The family appreciates all the prayers and support and would like time to grieve at this point."

Earlier Sunday, NASCAR spokesman Kerry Tharp said: "Everything that's been made available to us at this time would not preclude (Stewart) from participating in this event here today. But it's 9:30 in the morning."

He also said earlier that NASCAR has been monitoring the situation and will "honor the process and respect the timeline of the local authorities."

"Our thoughts and prayers go out to the family and friends and competitors and everyone involved at that complex up there," Tharp said. "While it was a non-NASCAR-sanctioned event, everyone in the motor sports community has feelings for these types of situations. We've been through them before."

Before Stewart withdrew from the race and about 15 minutes after his original comments, Tharp again emphasized that it was too early to say whether Stewart would be racing at Watkins Glen because NASCAR was still gathering information.

Greg Zipadelli, vice president of competition for Stewart-Haas Racing, announced Stewart would not race Sunday

After Zipadelli announced Stewart would not race, NASCAR released this statement: "Our thoughts and prayers go out to the family, friends, and fellow competitors of Kevin Ward Jr. We support Tony Stewart's decision to miss today's race and we will continue to respect the process and timeline of the local authorities and will continue to monitor this situation moving forward."

During Saturday night's sprint car race, Ward Jr. was spun out by Stewart, got out of his car to show his displeasure and then was struck by Stewart's car, sending Ward sliding down the track, fellow sprint car racer Tyler Graves and witness Adam Dulski told USA TODAY Sports.

"This is an ongoing investigation of an on-track crash," Ontario County (N.Y.) Sheriff Philip C. Povero said early Sunday morning.

Later Sunday afternoon, Povero said his investigation continues 16 hours after the deadly crash and that deputies are in Watkins Glen today to speak with Stewart or his representatives. Povero said he has seen no evidence to date of criminal intent on Stewart's part.

Povero asked witnesses and anyone with video of the crash to contact his office at (585) 394-4560. The sheriff also wants to talk with anyone with expertise in this type of racing.

Povero said authorities are waiting, among other things, on a forensic recreation of the crash and an autopsy on Ward by the Monroe County Medical Examiner's Office.

The crash was a topic of conversation early Sunday morning among race fans at Watkins Glen.

"Everybody was talking about it, and everybody has seen the video," said 42-year-old Leo Smith of Perinton, a suburb of Rochester, N.Y. Smith camped at the track and had spoken with 10-15 other fans by 7:30 a.m. "It's crazy," he said.

Dale Earnhardt Jr. tweeted Sunday: "We will all loose someone in our time. When a loss is sudden and unexpected, the pain & sadness is suffocating. Prayers for the Ward family."

We will all loose someone in our time. When a loss is sudden and unexpected, the pain & sadness is suffocating. Prayers for the Ward family.

"I can't see that anybody would've done anything intentional like that. (Stewart's) been great when he's with us. We've had a very good relationship with Tony. We've been proud to have him in our field. He's raced hard. He's raced clean. He respects what we have to offer. Even what he is, when he comes to our races, he's there to race. He's not under contract to some of these tracks, he just shows up."

Jeff Gordon will start on the pole for the Cheez-It 355 at The Glen. Stewart, a five-time Watkins Glen winner, qualified 13th.

"We know it's just an unbelievable tragedy," Zipadelli said during a hastily called news conference at 10:15 a.m. "Our hearts go out to Kevin and his family. Thoughts and prayers. This is a very tough, very emotional time for everybody -- his family, our family at Stewart-Haas, Tony Stewart."

Zipadelli said NASCAR had approved Smith to fill in and would help the team adjust the equipment for him.

In a statement, Bass Pro Shops, one of Stewart's primary sponsors on his No. 14 Chevrolet, said:

"All of us at Bass Pro Shops are all deeply saddened about last night's tragic accident at Canandaigua Motorsports Park. We send our thoughts and prayers to the family and friends of sprint car competitor Kevin Ward Jr and also to Tony Stewart and everyone at Stewart-Haas Racing."

Stewart, who co-owns the four-car stable Stewart-Haas Racing, could be eliminated from Chase for the Sprint Cup consideration by not starting. NASCAR's new playoff format rules include that drivers start each of the 26 races leading up to the Chase to be eligible. Stewart currently is 19th in points with no wins and would not make the 16-driver field without a win in one of the remaining five events before the cutoff.

"Honestly, that is the furthest thing from our minds right now," said Zipadelli, who indicated he would have supported whatever decision Stewart made. "We're thinking of Kevin's family and Tony and the people at our company. That's something that, when we get home on Monday, we'll have to look at and evaluate and go through that and make decisions. Today is all about doing what we can today to get through today and get through it the best we can as a group -- and try to do it in the right way.​ We haven't even crossed that bridge yet."

Stewart, a multimillionaire who broke his right leg in a sprint car accident in Iowa just over a year ago, will miss his first Cup start since missing the second half of 2013 to recover.

Ward's death comes on the heels of a tragic 2013 for sprint car racing:

--In March 2013, Dale Wondergem Jr., 68, and Marcus Johnson, 14, are killed when a car careens off Marysville Raceway Park and onto pit road in California. Johnson was the cousin of Chase Johnson, who was participating in the race but not involved in the crash. Wondergem owned a race car at the track.

--May 2013: Leroy Kay, 67, and David Richardson, 63, die from injuries incurred in a dirt 'dwarf' car race at Reno-Fernley Raceway in Reno, Nev. Dwarf cars use motorcycle engines and can run about 100 mph.

--June 12: Jason Leffler, 37, who ran in all three of NASCAR's circuits during his career, dies from injuries suffered in a sprint car crash at Bridgeport Speedway in Swedesboro, N.J. Leffler was a close friend of tewart's and roomed with him while he was working his way up NASCAR's ladder.

--July 16: During the final off week of the Sprint Cup season, Stewart triggered a multicar pileup while racing for the lead at Canandaigua (N.Y.) Motorsports Park. One of the drivers involved, 19-year-old Alysha Ruggles, suffered a back injury.

--July 29: Stewart flips five times while racing at Ohsweken Speedway, a dirt track in Ontario, Canada. He is uninjured and returns the next night to race a sprint car again.

--Aug. 4: Veteran hall of fame sprint car driver Kramer Williamson dies a day after being injured in a crash at Lincoln Speedway in Abbottsville, Pa.

--Aug. 5: Stewart is leading the main event at Southern Iowa Speedway when his sprint car hits a lapped car and flips. Stewart breaks his right leg.

In May 2006, Stewart pours water on someone below the stage as he waits during driver introductions at Richmond International Raceway. He got his first Cup win at the track in 1999. (Photo: Eileen Ryan, USA TODAY Sports)